How do you know this? A-A Astenah[sic] stated that the welds in the core were just construction welds.
From STJ911 angle cuts to Bazant buckling, I have heard so much crap and misinformation stated about core columns which flatly contradicts observed facts that I couldn't possibly give much weight to the above statement.
Core box columns were found for the most part very straight and separated into lengths of about 36n where n=1, 2. 3 (and even 4?)
Eight years after the event and most self-proclaimed experts probably aren't aware of that.
What is a 72' box column section? It is a straight piece where the weld held so well that nobody looking at the piece would even be aware of the location of the weld along it unless they where to told where to look.
This is why almost nobody can see all the core box column welds that held perfectly within the rubble.
What is a 98' straight box column? It is 2 consecutive welds holding perfectly while being subject to extreme abuse.
Please consider all the 36n where n=2, 3, 4 lengths of core column sections you can find in the rubble, perfectly straight, before you believe the WTC cores were tack or construction welded.
For example, in the photo below can anyone show me where some surviving core box column welds are? (You can't see them unless you know where to look).
Some of the welds were pretty strong, no?
Or the photo
The speared object is longer than 36 feet. Does that seem like a tack weld to you?
(On another subject: Look at the piece of flooring in the foreground in the photo above. How did it get so far from the base of either building?)